A new species of giant crayfish has been discovered in Tennessee that is twice the size of other species, researchers said Wednesday.

Scientists from the University of Illinois at Urbana-Champaign and Eastern Kentucky University found the first specimen of the new crustacean under a rock in a well-explored Tennessee creek.

The new species belongs to the genus Barbicambarus, which have distinctive “bearded” antennae, covered in hair-like bristles called setae that boost sensory awareness.

“This isn’t a crayfish that someone would have picked up and just said, ‘Oh, it’s another crayfish,’ and put it back,” said University of Illinois aquatic biologist Chris Taylor, who co-discovered the new species with Eastern Kentucky University biological sciences Professor Guenter Schuester.

“If you were an aquatic biologist and you had seen this thing, because of the size and the setae on the antennae, you would have recognized it as something really, really different and you would have saved it,” Taylor said in a statement.

The crustaceans, which can grow nearly as large as lobsters, are about 5 inches (12 cm) long and have been officially named Barbicambarus simmonsi.

“We spend millions of dollars every year on federal grants to send biologists to the Amazon, to Southeast Asia — all over the world — looking for and studying the biodiversity of those regions,” Schuster said.

“But the irony is that there’s very little money that is actually spent in our own country to do the same thing. And there are still lots of areas right here in the United States that need to be explored.”

North America is home to more than half of the world’s 600 known species of crayfish.

The report was published in the Proceedings of the Biological Society of Washington.